Naive question about grant/map

[Adam 'WeirdArms' Wiggins]

On Sat, 5 Dec 2003, Jonathan S. Shapiro wrote:

> On Fri, 2003-12-05 at 12:34, Joshua LeVasseur wrote:
> > On Dec 5, 2003, at 17:21, Jonathan S. Shapiro wrote:
>
> > If a mapping is missing from the kernel's cache...
>
> This statement is very closely related to my earlier question about
> mechanisms. When you use the term "mapping" above, what exactly do you
> mean:
>
>   1. A GPT?
>   2. Some other cache that is somehow constructed from a GPT?
>

	Jon you seem a bit confused ;) As Gernot already mentioned GPTs
are a page table implementation. Basically in L4 you have two VM data
structures. A page table per address space (GPTs being one such
implementation), and the mapping database which maintains the mapping tree
for each physical frame of memory in the system, this is only required to
implement the unmap/flush operation.

> The entire mapping DB is something that I am still failing to understand
> adequately.

	For a summary of the interaction between L4's VM API, the page
tables and the mapping database have a look at Chris's u/g thesis.
ftp://ftp.cse.unsw.edu.au/pub/users/disy/ug-theses/99-cls.ps.gz

	Cheers, Adam

--
Adam "WeirdArms" Wiggins           School of Computer Sci. & Eng.
PhD Student                        The University of NSW
Phone: +61 2 9385 7359             UNSW SYDNEY NSW 2052, Australia
Fax:   +61 2 9385 7942             http://www.cse.unsw.edu.au/~awiggins